Growth and fecundity of Schistosoma japonicum in mice maintained at different environmental temperatures.

On weeks 7 and 9 post infection (PI), the number of Schistosoma japonicum in mice maintained at low (5 degrees C) and high (32 degrees C and 35 degrees C) temperatures did not differ from those in controls (25 degrees C), but shorter males were observed in hosts at 5 degrees C. Further, both male and female worms recovered on week 7 PI from mice kept at 35 degrees C were shorter than those recovered from controls. Staining analysis revealed that worm maturation was not affected in mice kept at 5 degrees C and 32 degrees C. However, some female worms from mice kept at 35 degrees C had no eggs in the uterus. The day of patency of worms in the temperature-stressed mice did not differ from that in controls. EPG in mice kept at 32 degrees C rose to a high level on weeks 7-8 PI which was about 10 times as many as those in control mice, while EPG in mice kept at 5 degrees C appeared to be lower than in controls. The 7-week tissue egg count revealed that the hot- and cold-stressed mice supported significantly less egg productivity per female worm than control mice. The environmental temperature could not alter the migration pattern of schistosomula from the skin to lungs in mice.